The molecule of the element with an electronic configuration: 1s², 2s², 2p⁶ consists of ............
This shown diagram represents Lewis electron-dot symbol of the element ............ [Diagram: ·Ẍ:]
What is the number of the single electrons in Lewis electron-dot diagram of ₇N³⁻ ion?
Which of the following molecules includes three bond pairs?
What is the number of the electrons which share in the bond between the two carbon atoms in the molecule H₂C=CH₂?
What is the number of the electrons which participate in the formation of the covalent bonds in methane molecule CH₄?
What is the number of the lone pairs of electrons on arsenic atom ₃₃As in arsine AsH₃?
All the following molecules include bond pairs of electrons, except ............
The number of the free electrons on nitrogen atom in NH₃ equals the number of the free electrons on phosphorus atom in ............
One of the physical bonds is the ............
Among the elements ₉A, ₁₀B, ₁₁C and ₁₉D, the two elements that can combine together are ............
The table shows the number of the valence electrons of 4 elements, all lie in the same period in the periodic table, an ionic bond arises due to the combination of ............ [Table: (A)=1, (B)=2, (C)=6, (D)=7 valence electrons]
Calcium element ₂₀Ca forms an ionic bond with ............
Among the ionic compounds is ............
Which of the following compounds its melt is characterized by its ability to conduct electricity?
Which of the following has a distinct ability to conduct the electric current?
In which of the following compounds does the ionic character predominate?
Which sodium halide does have the highest melting point?
The elements W, X, Y and Z are located in the same period in the periodic table. Which of the chlorides of these elements has the highest melting and boiling points?
The chemical formula of the compound produced by the combination of element Y: [Ne], 3s², 3p⁴ with element X: [Ne], 3s² is ............
When two oxygen atoms combine together to form oxygen molecule, ............
In which molecule do the bond electrons spend equal times in the vicinity of each of two bonded atoms?
When two atoms of an element whose atomic number is (9) combine together, then the bond in the produced molecule will be ............
The following table shows the electron configurations of 4 elements:
| (1) 1s2, 2s2, 2p1 | (2) 1s2, 2s2, 2p5 |
| (3) 1s2, 2s2, 2p6, 3s1 | (4) 1s2, 2s2, 2p6 |
The symbol (δ⁺) is put on the upper right of ............
The following compounds are polar covalent compounds, except ............
What are the two elements which combine together forming a covalent compound?
Which of the following substances is a covalent compound?
The opposite figure represents ............
In terms of the opposite table:
| Element | H | C | N | O |
| Electronegativity | 2.1 | 2.5 | 3 | 3.5 |
Which of the following molecules is more polar? [Knowing that the electronegativities are: H = 2.1, N = 3, O = 3.5, F = 4]
Which of the halogen atoms that surround the carbon atom in the opposite molecule attracts the bond electrons more?
Which of the following choices represents one of the atoms forming the molecule of hydrogen cyanide HCN?
Which of the following elements of group (2A) forms compounds that exhibit the properties of the covalent compounds?
Which of the following two elements the covalent bond that arises between their atoms is the most polar?
Both the cation and the anion of each of the following ionic compounds contain the same total number of electrons, except ............ [Knowing: H=1, Li=3, N=7, F=9, Na=11, O=8, Cl=17, Ti=22]
The opposite table shows the atomic numbers of the two elements (X) and (Y), and the charge of the ion of each of them when it combines with magnesium ion.
| Element | Atomic number | Charge of the ion |
|---|---|---|
| (X) | n | −2 |
| (Y) | n + 1 | ? |
| Choices | Type of bonding | Chemical formula |
|---|---|---|
| (a) | Ionic | XY₂ |
| (b) | Covalent | XY₂ |
| (c) | Ionic | X₂Y |
| (d) | Covalent | X₂Y |
Which of the following molecules contains two types of chemical bonds?
Draw Lewis electron-dot symbol of an atom of a representative element (X) which contains 3 principal energy levels, and its outermost level contains 2 unpaired electrons only.
Determine the type of the chemical bond in the following molecules:
| Element | Electronegativity |
| S | 2.5 |
| H | 2.1 |
| Ca | 1 |
| K | 0.8 |
| Cl, N | 3 |
| O | 3.5 |
Give reason: (1) The melting point of table salt is higher than that of magnesium chloride salt. (2) The bond between carbon and hydrogen in methane molecule is non-polar. (3) The bond in water molecule is polar covalent bond, while that in chlorine molecule is pure covalent bond.
Write the electronic configuration of the elements ₁₇Cl and ₂₀Ca. Then conclude the type of the bond that would be formed between them and the formula of the product of their combination together.
Assisted by the opposite figure:
Three elements (W), (X) and (Y):
Based on the elements: (₃A, ₆B, ₃₃C, ₃₇D) Determine the elements which react with chlorine forming: (1) A molecule that contains more than one bond pair. (2) A compound that has the highest melting point.
Illustrate the type of chemical bonding in each of the following molecules:
In terms of the following table which shows the electronegativities of some elements:
| The element | H | Na | Cl | Ca | K | Mg | C | Br | N | P | I | F | O |
| The electronegativity | 2.1 | 0.9 | 3 | 1 | 0.8 | 1.2 | 2.5 | 2.8 | 3 | 2.1 | 2.5 | 4 | 3.5 |
Choose from the following pairs of bonds the more polar bond in each pair, with giving reason: